This invention relates to an inflatable air or gas bag for use as a component of a passenger restraint system, especially in motor vehicles, a process for folding the inflatable gas bag to a prescribed shape and volume by introducing it into a folding tool in an uninflated collapsed state, as well as to an apparatus for performing the process, including a folding tool as a receiving station for the gas bag.
German patent document (DE-44 22 276) discloses an air bag, a process for its folding, and an apparatus for implementing the folding process. In this disclosure, a main purpose, among other things, is to fashion the air bag so that it can deploy very quickly and without impediment, and, if possible, in all directions simultaneously. To this end, the air bag possesses main and secondary fold lines. Emanating from an imaginary center of a fully deployed air bag, there is a type of concentric zig-zag or accordion folding. This alternating folding is accomplished with aid of dish-like elements having cylindrical walls that inter-engage into one another, with varying diameters for the dish-like elements that lie opposite one another. Radially-acting folding elements, as grasping elements which are arranged in oppositely positioned pairs, are caused, one after the other, to move radially inwardly and press together. In this process, the next outer folding element is removed as the grasping elements proceed further inwardly. In a last step, the grasping apparatus is moved, together with the air bag, into a packing apparatus.
In the German patent document DE-195 16 264 C1, a grasping apparatus is disclosed in which ends of grasping elements are slit and guided in such a manner that they cross each other at their ends. These ends protrude farther if the grasping elements are moved farther into one another.
German patent document DE-195 35 564 A1 discloses a process and an apparatus for folding an gas/air bag for an air bag module. In the process, folding is accomplished by sucking the air bag from an upper or lower portion of a folding tool. No so-called folding elements are provided. A grasping element is a tightening strip that is pulled by a pressure cylinder with aid of deflection rollers, with the tightening strip being supported by gripping jaws which also change their positions until they abut adjustable contact base plates.
An additional process of this type is disclosed in German patent document DE-195 16 494 C1. In this case, a gas bag is brought into its in-use form prior to folding, that is, it is inflated, so that a base fabric area of the gas bag is arranged upon a working platform and another fabric surface is convexly curved. In this state, mechanical folding aids engage the gas bag and fold it, single ply. This process is too expensive and difficult to control in an automated process of folding, because a continual introduction/escape of gas must be assured, on the one hand, or, additional apparatus that hold the gas bag in its deployed form during folding, must be coordinated with the folding aids.
It is an object of this invention to provide a gas bag, as well as an effective process, for automated folding, and an apparatus therefor.